BioShock - The Omega Strain - Big DaddyLittle Sister
by NykkiLeigh
Summary: After BioShock 3: While exploring the deepest parts of their destroyed city, Rapture, A Little Sister found a new Strain of ADAM that gives back the Intelligence to Little Sisters, Big Daddies, and Big Sisters, and when her Big Daddy faces a violent form a protection, he deals with the only other injection of it besides the Little Sister, causing new feelings & sensations to arise.


_Author's Note 1: My best friend (who is a HUG fan of the game) helped come up with the concept for this story :)_

 _Author's Note 2: In this Universe, the Big Daddies and Little Sisters were the experimental step after the Alpha, Beta, and Delta, which is why they are both bigger and little more advanced with their "intelligence." This Little Sister is around 16 and the Big Daddy is 21._

Little Sister's syringe was almost full. She was on her knees, watching, mesmerized by the glowing crimson liquid that was filling the cylinder. She pulled it out of the back of the corpse's neck, letting it fall with an audible "plop." She looked around the desolate place hidden deep in Rapture. She felt a stirring in her chest that she wasn't used to. Her new found intelligence told her it was sadness. Her home hadn't always looked like this.

She stood, turning to head back to her Big Daddy when a Splicer soared through the air at her, a shriek that could only be described as "psychotic" piercing her ears. She flung her arms over her face, and screamed. Suddenly, Big Daddy was in front of her, red-eyed (a symbol of his rage), hand out towards the splicer, sending it 10 feet backwards on impact. In the blink of an eye he had her by the waist and flung her up so her tiny form was on his shoulder. He was ginormous, even by a normal person's standards, so on top of him, Little Sister felt like she was on top of the world – literally.

She knew they were in trouble. The shriek had attracted other Splicers. She then remembered the newly-filled syringe in her hand and without hesitation plunged it into her Big Daddy's neck. He let out an animalistic roar and she covered her ears. She felt bad, knowing he would be in excruciating pain, but just long enough for the Splicers to close in. He was still screaming, and suddenly, it stopped. He stood, slightly hunched over and breathing heavy, when suddenly he straightened, turned to look at Little Sister, then back at the Splicers around them.

He growled, low in his throat. He then spoke his first words: "You want Little Sister, you go through Big Daddy." Suddenly a giant drill broke through his skin and through the suit with an audible _rip_ followed by the loud sound of a drill spinning.

He took a step towards the Splicers and they charged two at a time. His giant form just had to turn slightly, arm extended, to make contact with the first, ripping through its abdomen violently. He swung backwards, getting the other one, cutting it completely in half. Little Sister held on tight, frightened, but also thoroughly entertained.

The Splicers kept coming, faster, wilder, and Big Daddy cut through each of them with a roar, his drill splattering their blood all over the ground until the last one was finally dead, shredded on the ground beneath them.

He ran suddenly, afraid the Splicers would be attracted to the scent, the blood. He didn't stop until he was on the outskirts of their city. There was no one around to be seen or heard. No threats to his Little Sister.

"Big Daddy…" Little Sister's soft voice rang in his ears and he turned to look at her. Her eyes were wide in disbelief of the carnage of what she had just seen. His eyes switched immediately to green, a sign of his swift mood change, and he gently set her down and went to hug her. She took a step back and he was hurt.

Hurt. A…feeling? How unfamiliar. He then realized she wasn't SCARED of him, his suit was covered in blood. He grabbed his large helmet, pulling it off, and pulled the bulky clothes off of himself. He stood before her, light shaggy hair hung over his blue eyes, now full of the wonder and intelligence he didn't have before. His 9 foot, broad figure was dressed in dark jeans, a white wife beater, a leather jacket, and big black boots. His eyes were a brilliant blue.

She ran and jumped up into his arms, her 5 foot slender figure completely enclosed against his chest. He had never felt her against him, not this way, not without the suit. She was so...frail. So soft…so warm. He felt a stirring deep in his belly, another unfamiliar sensation. She buried her face in his neck and inhaled deeply.

"Thank you, Big Daddy."

He cleared his throat but his voice still came out low and gravelly. "You're welcome, Little Sister." He hoped it was just the new use of his vocal chords that made him like this.

She wiggled out of his grasp and looked up at him with big, wondering eyes. "How do you feel?"

"Hungry." The word came out in more of a growl than intended.

She tilted her head to one side. "Hungry?"

Big Daddy was suddenly frustrated. He had this…urge he didn't understand. It was similar to aggression, but he knew he couldn't be feeling that I _towards_ his Little Sister. So what was this? He wanted to ravage her? But how did that make any sense?

"Big Daddy?" He snapped out of his thoughts and looked down at her. "Big Daddy, you're growling at me."

He suddenly felt…sad? Another new feeling? What the fuck was happening?

"N-no…I…" He was having trouble getting it out.

She looked up at him with sympathy. "I know," she wrapped her arms around him and squeezed. "I understand."

Her breasts pressed flush against the top of his crotch and he growled, louder this time. She tilted her head back to look at him, confused. Suddenly understanding washed over her face. She wasn't sure how exactly she understood, but she did. She pressed against him tighter, not taking her eyes off his face.

"I…I know what you want." A blush spread across her cheeks.

She was….embarrassed? What was wrong? More frustration spread throughout his body because he KNEW he needed to protect her, to fix what was wrong. But he couldn't even figure out what was wrong with HIM.

"Big Daddy…?" It came out more as a question as she reached up and touched his face. She ran her fingertips across his lips, and her other hand moved down, pausing as she felt his hard member under his jeans. She bit her lip, eyes still wide as she slowly unzipped his jeans. She trailed her other hand down his chest and stomach, then finally over the button as she popped it open.

She looked down as his jeans fell, eyes glued on his dick. Big Daddy wasn't sure what to do. He had never felt this before, never experienced this before. He wasn't sure what was going on, but somehow he knew it felt right.

Her hand wrapped around him and he let out a soft growl, low in his throat. "Big Daddy…let me help you?"

She squeezed his thick cock gently and he inhaled sharply. "Yes, Little Sister."

She dropped to her knees and began gently stroking him, getting him to full hardness before putting his head into her mouth. He growled louder and she slid down farther, lips straining over his length. She began moving back and forth, slow at first, then faster as he got more used to the feeling.

Her mouth was so warm, so wet. It was perfect. He groaned as he watched his cock disappear and reappear from her lips. Her eyes were closed, brows slightly furrowed as she struggled to take all of him again and again. He suddenly felt his lower belly tighten and growled loud, pulling back and letting his dick fall from her mouth.

"Big Daddy?" She looked up at him in wonder, and a little hurt.

He picked her up by her waist so her face was in front of his. "I need…more." He pressed his lips to hers. He slid his tongue against hers, cock throbbing as he heard her small moan. She was responding to his kiss, her whole body warming in his hands, her breathing becoming labored. He growled again. "More!"

He laid her down, gently despite the incessant need he felt and her legs fell open before him. Her dress had hiked up revealing the tiny white fabric between her legs, the evidence of her arousal quite clear.

He leaned in close and inhaled deeply. "So…wet."

Her chest was rising and falling quickly as she unbuttoned her dress completely. "Just for you, Daddy."

He stared at her bare breasts for what seemed like a long while before climbing up her body and taking one into his mouth. He sucked hard, then swirled his tongue around the hard nipple when she arched her back for him. He did the same to the other, but this time squeezing the other with his giant hand. She was moaning and wiggling beneath him, and he could sense she was aching. It was his instinctive duty to help her, fix what was wrong, and by God he was going to fucking do it now.

He slowly ran his tongue down her stomach to her panty line. It was such a strange phenomenon: he was used to acting on instinct, running on nothing but feeling and adrenaline, but it was always to inflict unrelenting pain to anyone who dared to threaten his little sister, his little girl,but never pleasure. But anything for his little girl. Without thinking, he ripped her panties away, tossing the shred of fabric aside. She looked down at him between her legs, eyes wide and wild with arousal. He looked down at the wetness that pooled between her legs. He stared at how pink and swollen she was. He needed a taste. He growled low in his throat and dove in, sliding his tongue up into her, loving the way she tensed and then moaned for him. He swirled his tongue deep inside, her velvety walls squeezing his tongue. She tasted so sweet. He pulled his tongue out and licked up the entirety of her pussy, then slowly lapped at her swollen clit. She moaned louder, the sound music to his ears. He needed to make her do it again. He wanted to hear it over and over again. He sucked hard again and again and her moans became louder, her breathing more intense.

"Mmm…Big Daddy!" She cried out and her small frame tensed underneath him as her juices flooded the ground beneath them. He automatically slid his tongue down to catch them in his mouth, flicking his tongue against her entrance for added pleasure.

He slowed his licks as she came down until she went limp. He crawled on top of her and looked down at her eyes. She looked up at him and smiled at him.

He leaned down and whispered in her ear. "More."

He flipped them over and let her straddle him. She was small enough that her knees didn't touch the ground as her soaking pussy sat against the underside of his dick. She looked at him, biting her lip, and began slowly sliding against him. He growled and grabbed her hips. She moved faster, the friction against her clit making her moan as her dark hair fell in front of her face. "Mmm…Little Sister…"

He moved her a little farther up and she gasped as his tip poked her entrance. She stared at him, wide-eyed as the head popped in. She gasped and bit her lip. He slid in, inch by tantalizing inch, giving her enough time to adjust to his size. When he was finally balls-deep inside of her, her soft, wet walls clamped down on him hard so he felt every delicious inch of her surrounding his cock. She moaned as she felt him throb and slowly began moving her hips. Big Daddy's hands slid up to her breasts, squeezing them as they swayed slightly.

She moved faster, her moans becoming more and more needy until she was bouncing quickly on his dick. He had one large hand around her hip, the other squeezing her breast. He thrusted up to get just as much friction, moaning as her wetness slid down his shaft and to his balls on every down stroke.

"Ooh…Big Daddy!"

She moved faster and he fucked her harder, the sound of skin on skin bringing them closer to the edge.

"Please, Big Daddy, make me cum!"

He growled as their movements became more fervent. He slammed her down on his cock as he fucked her harder, faster.

"Cum for me, Little Sister!"

She screamed and squeezed around his huge cock, cumming hard for him. Big Daddy gave two more powerful thrusts upward and roared loud, shooting his cum into her tightening pussy. She collapsed on his chest, quivering in the aftermath. He immediately wrapped his large arms around her, holding her close. He kissed her hair gently.

"I love you, Big Daddy."

"I love you, too, Little Sister."

 _Author's Note: Be on the lookout for my Big Daddy/Little Sister/Big Sister and Big Sister/Little Sister one-shots!_


End file.
